; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes='default<O3>' -rotation-max-header-size=0 -S < %s | FileCheck %s --check-prefix=HOIST
; RUN: opt -passes='default<O3>' -rotation-max-header-size=1 -S < %s | FileCheck %s --check-prefix=HOIST
; RUN: opt -passes='default<O3>' -rotation-max-header-size=2 -S < %s | FileCheck %s --check-prefix=ROTATE
; RUN: opt -passes='default<O3>' -rotation-max-header-size=3 -S < %s | FileCheck %s --check-prefix=ROTATE
; This example is produced from a very basic C code:
;
; void f0();
; void f1();
; void f2();
;
; void loop(int width) {
; if(width < 1)
; return;
; for(int i = 0; i < width - 1; ++i) {
; f0();
; f1();
; }
; f0();
; f2();
; }
; We have a choice here. We can either
; * hoist the f0() call into loop header,
; * which potentially makes loop rotation unprofitable since loop header might
; have grown above certain threshold, and such unrotated loops will be
; ignored by LoopVectorizer, preventing vectorization
; * or loop rotation will succeed, resulting in some weird PHIs that will also
; harm vectorization
; * or not hoist f0() call before performing loop rotation,
; at the cost of potential code bloat and/or potentially successfully rotating
; the loops, vectorizing them at the cost of compile time.
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
declare void @f0()
declare void @f1()
declare void @f2()
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture)
define void @_Z4loopi(i32 %width) {
; HOIST-LABEL: @_Z4loopi(
; HOIST-NEXT: entry:
; HOIST-NEXT: [[CMP:%.*]] = icmp slt i32 [[WIDTH:%.*]], 1
; HOIST-NEXT: br i1 [[CMP]], label [[RETURN:%.*]], label [[FOR_COND_PREHEADER:%.*]]
; HOIST: for.cond.preheader:
; HOIST-NEXT: [[SUB:%.*]] = add nsw i32 [[WIDTH]], -1
; HOIST-NEXT: br label [[FOR_COND:%.*]]
; HOIST: for.cond:
; HOIST-NEXT: [[I_0:%.*]] = phi i32 [ [[INC:%.*]], [[FOR_BODY:%.*]] ], [ 0, [[FOR_COND_PREHEADER]] ]
; HOIST-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i32 [[I_0]], [[SUB]]
; HOIST-NEXT: tail call void @f0()
; HOIST-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY]]
; HOIST: for.cond.cleanup:
; HOIST-NEXT: tail call void @f2()
; HOIST-NEXT: br label [[RETURN]]
; HOIST: for.body:
; HOIST-NEXT: tail call void @f1()
; HOIST-NEXT: [[INC]] = add nuw i32 [[I_0]], 1
; HOIST-NEXT: br label [[FOR_COND]]
; HOIST: return:
; HOIST-NEXT: ret void
;
; ROTATE-LABEL: @_Z4loopi(
; ROTATE-NEXT: entry:
; ROTATE-NEXT: [[CMP:%.*]] = icmp slt i32 [[WIDTH:%.*]], 1
; ROTATE-NEXT: br i1 [[CMP]], label [[RETURN:%.*]], label [[FOR_COND_PREHEADER:%.*]]
; ROTATE: for.cond.preheader:
; ROTATE-NEXT: [[CMP13_NOT:%.*]] = icmp eq i32 [[WIDTH]], 1
; ROTATE-NEXT: br i1 [[CMP13_NOT]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_BODY_PREHEADER:%.*]]
; ROTATE: for.body.preheader:
; ROTATE-NEXT: [[TMP0:%.*]] = add nsw i32 [[WIDTH]], -2
; ROTATE-NEXT: br label [[FOR_BODY:%.*]]
; ROTATE: for.cond.cleanup:
; ROTATE-NEXT: tail call void @f0()
; ROTATE-NEXT: tail call void @f2()
; ROTATE-NEXT: br label [[RETURN]]
; ROTATE: for.body:
; ROTATE-NEXT: [[I_04:%.*]] = phi i32 [ [[INC:%.*]], [[FOR_BODY]] ], [ 0, [[FOR_BODY_PREHEADER]] ]
; ROTATE-NEXT: tail call void @f0()
; ROTATE-NEXT: tail call void @f1()
; ROTATE-NEXT: [[INC]] = add nuw nsw i32 [[I_04]], 1
; ROTATE-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i32 [[I_04]], [[TMP0]]
; ROTATE-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_COND_CLEANUP]], label [[FOR_BODY]]
; ROTATE: return:
; ROTATE-NEXT: ret void
;
entry:
%width.addr = alloca i32, align 4
%i = alloca i32, align 4
store i32 %width, ptr %width.addr, align 4
%i1 = load i32, ptr %width.addr, align 4
%cmp = icmp slt i32 %i1, 1
br i1 %cmp, label %if.then, label %if.end
if.then:
br label %return
if.end:
call void @llvm.lifetime.start.p0(i64 4, ptr %i)
store i32 0, ptr %i, align 4
br label %for.cond
for.cond:
%i3 = load i32, ptr %i, align 4
%i4 = load i32, ptr %width.addr, align 4
%sub = sub nsw i32 %i4, 1
%cmp1 = icmp slt i32 %i3, %sub
br i1 %cmp1, label %for.body, label %for.cond.cleanup
for.cond.cleanup:
call void @llvm.lifetime.end.p0(i64 4, ptr %i)
br label %for.end
for.body:
call void @f0()
call void @f1()
br label %for.inc
for.inc:
%i6 = load i32, ptr %i, align 4
%inc = add nsw i32 %i6, 1
store i32 %inc, ptr %i, align 4
br label %for.cond
for.end:
call void @f0()
call void @f2()
br label %return
return:
ret void
}
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